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排序方式: 共有224条查询结果,搜索用时 23 毫秒
1.
覆膜滴灌条件下,采用静态箱-气相色谱法研究了不同施肥策略:CK(不施肥)、CF(N 300 kg/hm~2;P2O590 kg/hm~2;K2O 60 kg/hm~2)、60%CF+OF(普通有机肥6 000 kg/hm~2)、60%CF+BF(生物有机肥6 000 kg/hm~2)对棉田土壤N_2O排放的影响,旨在明确滴灌棉田连续不同施肥策略下土壤N_2O的排放特征。结果表明,棉花生育期N_2O排放通量表现为施肥处理大于不施肥处理,滴灌施肥后第3/4天N_2O排放通量顺序为CF60%CF+OF60%CF+BFCK,而滴灌后第7/8天N_2O排放通量则表现为有机肥处理高于化肥处理,滴灌施肥结束后表现与之相同;生育期的N_2O排放总量以100%化肥处理(CF)最高,与其相比,60%CF+OF和60%CF+BF处理分别降低3.75%和8.37%,N_2O排放系数则分别降低1.39%和73.8%;相关及通径分析均表明,与土壤NH+4-N相比,NO-3-N与N_2O排放的关系更密切。 相似文献
2.
一种含有竹叶黄酮的复配型肉类食品添加剂的开发 总被引:5,自引:0,他引:5
通过竹叶黄酮和异Vc钠的系列复配应用试验,得到了一种性能优越的肉类食品添加剂.实验选用中式香肠体系,通过测定过氧化值(POV)、酸价(AV)和亚硝酸盐含量,辅以感官评定等手段,评价此复合抗氧化剂的抗氧性能以及对产品风味和质量的整体影响.结果表明,在原配方的基础上,硝酸盐或亚硝酸盐减半使用,同时添加0.01%的竹叶黄酮和0.05%的异Vc钠,能显著抑制香肠的脂质过氧化,延长产品保质期,降低产品中亚硝酸盐的含量,同时维持并改善中式香肠应有的感官品质.竹叶黄酮在有效发挥抗氧化作用的同时,部分替代了具有潜在致癌作用的发色剂,提高了制品的安全性,是一种十分有前途的肉类食品添加剂. 相似文献
3.
4.
5.
池塘中亚硝酸盐对草鱼种的毒害及防治 总被引:45,自引:2,他引:45
亚硝酸盐对草鱼种有很高的毒性,特别是水温超过30℃以上时。它主要是诱导草鱼血液中的血红蛋白转变为高铁血红蛋白,高铁血红蛋白超过血红蛋白总量的23.0%时,容易诱发草鱼出血病。随着草鱼血液中高铁血红蛋白的增高,红细胞数量和血红蛋白含量逐渐减少。池中亚硝酸盐氮含量到0.099±0.03毫克/升时,草鱼会出现出血病。清除水中亚硝酸盐氮的方法是在池塘中施加次氯酸钠,亚硝酸盐氮超过0.15毫克/升时,最好在池塘中先施加熟石灰,然后施加次氯酸钠,且以分次施用,效果较好。 相似文献
6.
[目的]研究不同溶剂的假蒟叶提取物对亚硝化反应的影响。[方法]在模拟胃液条件下,测定假蒟叶提取物亚硝酸盐清除率及亚硝胺合成阻断率。[结果]不同溶剂的假蒟提取物均有一定的抑制亚硝化反应作用,其中乙酸乙酯提取物的抑制作用最强,且其对亚硝酸盐的清除率及对亚硝胺合成的阻断率在一定的浓度范围内随其浓度的增加而增加,对亚硝酸盐清除能力较强,其IC50值为0.425mg/ml,对亚硝胺合成阻断的能力相对较低,其IC50值为4.064 mg/ml。[结论]假蒟叶提取物具有较好的亚硝化反应抑制活性且主要通过清除底物亚硝酸盐来实现。 相似文献
7.
建立山羊亚硝酸盐中毒模型,用棉签分别蘸取口液、尿液立即滴加偶氮试剂均显粉红色,中毒后10~20min显浅粉红色;60min显深粉红色,随中毒症状加重,棉签显色相应加深,甚致变为棕红色。同时棉签显色加深和血液褐变程度加重与MHb/Hb比值升高同步。此种诊断方法是诊断亚硝酸盐中毒的动物可靠、灵敏和快速的诊断方法。 相似文献
8.
Thiosulfate and CS2 inhibit nitrification. The effect of the addition of thiosulfate on the turnover of inorganic N compounds was tested in an Egyptian and a German arable soil under nitrifying and denitrifying conditions. For nitrification, the soils were amended with NH
inf4
sup+
and incubated under aerobic conditions. For denitrification, the soils were amended with NO
inf3
sup-
and incubated under anaerobic conditions. In both cases, the thiosulfate decreased with time while tetrathionate accumulated to an intermediate extent. Both compounds disappeared completely after <25 days. Production of CS2 was not observed. Carbonyl sulfide was produced only in the Egyptian soil, but production decreased with increasing amounts of added thiosulfate. Under nitrifying conditions, the addition of increasing amounts of thiosulfate (25, 50, and 100 g S g-1 dry weight) resulted in decreasing rates of NH
inf4
sup+
oxidation to NO
inf3
sup-
; it also resulted in an increasing intermediate accumulation of NO
inf2
sup-
and NO, and in an increasing production of N2O. Under denitrifying conditions, the addition of increasing amounts of thiosulfate did not significantly affect the rate of NO
inf3
sup-
reduction, and resulted in an increasing intermediate accumulation of NO
inf2
sup-
and of NO only in the German soil in which the production of N2O was slightly inhibited by thiosulfate. These results demonstrate that the nitrification of NH
inf4
sup+
and NO
inf2
sup-
was inhibited by increasing concentrations of thiosulfate and/or tetrathionate without involving the formation of volatile S compounds as potential nitrification inhibitors. Denitrification was not affected by the addition of thiosulfate. 相似文献
9.
Denitrification and fermentation in plant-residue-amended soil 总被引:1,自引:0,他引:1
Summary Nitrous oxide production (denitrification) during anaerobic incubation of ground-alfalfa-, red-clover-, wheat-straw-, and cornstover-amended soil was positively related to the initial water-soluble C content of the residue- amended soil. The water-soluble C concentration decreased in all treatments during the first 2 days, then increased in the alfalfa-, red-clover-, and wheat-straw-amended soil until the end of the experiment at 15 days. An accumulation of acetate, propionate, and butyrate was partly responsible for the increased water-soluble C concentration. Denitrification rates were much higher in the alfalfa-and red-clover-amended soil, but NO
3
–
was not fully recovered as N2O in these treatments. Supported by earlier experiments in our laboratory, we conclude that some of the NO
3
–
was reduced to NH
4
+
through fermentative NO
3
–
reduction, otherwise known as dissimilatory NO
3
–
reduction to NH
4
+
. Acetate, the primary product of anaerobic fermentation, accumulated in the alfalfa- and red-clover-amended soil in the presence of NO
3
–
, supporting previous observations that the processes of denitrification and fermentation occur simultaneously in C-amended soil. The partitioning of NO
3
–
between denitrification and fermentative NO
3
–
reduction to NH
4
+
depends on the activity of the denitrifying and fermentative bacterial populations. NO2 concentration may be a key in the partitioning of NO
3
–
between these two processes. 相似文献
10.
Ammonium oxidation coupled to dissimilatory reduction of iron under anaerobic conditions in wetland soils 总被引:1,自引:0,他引:1
Jean-Christophe Clément Junu Shrestha Peter R. Jaffé 《Soil biology & biochemistry》2005,37(12):2323-2328
In exploring the dynamics of iron and nitrogen cycling in sediments from riparian forests we have observed a redox reaction that has not been previously described. During incubations of soil slurries under strictly anaerobic conditions, we repeatedly measured an unexpected production of both nitrite () and ferrous iron [Fe(II)]. Using this indirect evidence we hypothesize that, under anaerobic conditions, there is a biological process that uses ferric iron [Fe(III)] as an electron acceptor while oxidizing ammonium () to for energy production. This oxidation under iron reducing anaerobic conditions is thermodynamically feasible and is potentially a critical component of the N cycle in saturated sediments. 相似文献